The effect of estradiol on the production of melatonin in postmenopausal women.

The influence of two routes of estradiol administration on pineal melatonin production in postmenopausal women was investigated. Both transdermal and oral estradiol treatment led to an increase as well as decrease of melatonin production in different patients. The reason why individuals respond either in a stimulatory or inhibitory manner is unknown and requires to be evaluated in further more extensive studies.